Conventionally, there has been performed a test in which a vehicle is collided with a dummy object having a shape of a human for obtaining information indicating a condition of each part of a human body upon the collision based upon the information from various sensors attached to the dummy object, such as an acceleration sensor, load sensor, and displacement sensor, in order to strengthen the safety of pedestrians upon the collision of a vehicle (refer to Japanese Utility Model Examined Patent application No. HEI6-34671).
However, since the conventional dummy object presupposes a vehicle collision, it is not effective for the prediction of collision between pedestrians and a vehicle that has recently been developed. Specifically, a collision prediction apparatus for a vehicle that has recently been developed uses a millimeter wave radar and image sensor to predict and cope with the collision before the vehicle actually collides a pedestrian.
The present inventors have formed a dummy object (so-called mannequin) into a shape of a human with the use of a material having less reflection of electric wave (e.g., foam member such as styrene foam), dressed the dummy object to make a dummy doll 1, and put this dummy doll 1 in front of a vehicle, as shown in FIG. 13. Then, the present inventors have operated a collision prediction apparatus mounted to a vehicle and composed of a millimeter wave radar 2, plural image sensors 3, and a computer 4, thereby conducting a test or inspection pertaining to a collision prediction to a pedestrian. Alternatively, the present inventors have operated a collision prediction apparatus that is not yet mounted to a vehicle and is composed of a millimeter wave radar 2, plural image sensors 3, and a computer 4, or the components of the collision prediction apparatus, thereby conducting the aforesaid test or inspection.
However, the present inventors have found through this test or inspection that the result of this test or inspection is different from the result of a test or inspection in which an actual human is made stand in front of the collision prediction apparatus. In view of this, the present inventors have found from various experiments that the change with time of the intensity of the reflection wave inputted by the millimeter wave radar 2 is different between the case of the actual human and the case of the dummy doll 1. Specifically, the present inventors have found that the change with time of the reflection intensity of a millimeter wave is different between the case of the actual human and the case of the dummy doll 1. FIG. 14 shows a result of the experiment showing the difference in the reflection intensity of a millimeter wave. The change of the reflection intensity of a millimeter wave with time by the dummy doll 1 is very small as indicated by a solid line obtained by linking black squares. On the other hand, the change of the reflection intensity of a millimeter wave with time by the actual human is great as indicated by a broken line obtained by linking black triangles. It is to be noted that, in the case of human, the result of the undressed state is the same as in the dressed state.
As a result of the further experiment, the present inventors have found that the change with time of the reflection intensity of a millimeter wave is increased by swaying the clothing put on the dummy object (see the solid line obtained by linking black circles in FIG. 2). It is estimated that this phenomenon is caused by the following fact. Specifically, the cloth constituting the clothing has a characteristic of transmitting a part of the millimeter wave and reflecting a part thereof, and the state of the cloth in the advancing direction of the millimeter wave changes with time by the swaying movement of the cloth. Further, the present inventors have thought of a reflection plate, which reflects the millimeter wave, attached to the dummy object, and made the experiment for this. In this case, the present inventors have confirmed that the change with time of the reflection intensity of the millimeter wave increases particularly by changing the state of the reflection plate (see the solid line obtained by linking black circles in FIG. 7).